code: def get_dummy_series(
      ts_length: int, lt_end_value: int = 10, st_value_offset: int = 10
  ) -> TimeSeries:
      return (
          lt(length=ts_length, end_value=lt_end_value)
          + st(length=ts_length, value_y_offset=st_value_offset)
          + rt(length=ts_length)
      )
  
imports: import random
  from itertools import product
  import numpy
  import pandas
  import pytest
  from darts import TimeSeries
  from darts.datasets import AirPassengersDataset, MonthlyMilkDataset
  from darts.logging import get_logger
  from darts.metrics import mape, r2_score
  from darts.models import ARIMA, FFT, ExponentialSmoothing, NaiveDrift, NaiveSeasonal, Theta
  from darts.tests.conftest import tfm_kwargs
  from darts.utils.timeseries_generation import gaussian_timeseries
  from darts.utils.timeseries_generation import linear_timeseries
  from darts.utils.timeseries_generation import random_walk_timeseries
  from darts.utils.timeseries_generation import sine_timeseries
label_desc: Use image node_id 1 for calling a global function with example usage: get_dummy_series(ts_length, lt_end_value, st_value_offset) and returns: unknown